A Note on the Histological Appearance of Periodontal Tissues Associated with Premature Loss of Incisor Teeth in Sheep

Abstract

SUMMARY Histological sections were prepared of the central incisor teeth and surrounding tissues of 48 sheep of varying ages from flocks (A and B) in which loss of incisor teeth was rare, and of similar tissue from 54 sheep from flocks (C, D, E and F) in which premature loss of incisor teeth was common. In young animals the sulcus or groove between the gum and central incisor was slightly deeper in ewes from flocks D, E and F than in those from flocks A and B. At 2½ years this difference was very marked, the sulcus having deepened to form a ‘pocket’, and there were large concentrations of round cells around the epithelial attachments in animals from the former flocks compared with only a small number of round cells in similar tissue from the latter flocks. At 3½ years these differences were still more striking and, in addition, some resorption of alveolar bone had occurred in animals from flocks D, E and F, but not in those from flocks A and B. Material available from flock C of this age resembled that from flocks D, E and F more than that from flocks A and B. At 4½ years the central incisor teeth of ewes from flocks C, D, E and F were either missing or much resorption of alveolar bone had occurred, while in animals from flocks A and B there were relatively small differences in the appearance of periodontal tissue at this age, or even at 6½ k years, from those of ewes aged 1½ years. The possible relevance of these observations to the aetiology of premature loss of incisor teeth in sheep is discussed.